• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
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    • 专利摘要:
    PURPOSE: An inductively coupled plasma generator having a serpentine coil antenna is provided to enhance the uniformity of plasma, reduce the inductance of an antenna, and restrict a capacitive coupling effect by improving a structure of the inductively coupled plasma generator. CONSTITUTION: An inductively coupled plasma generator having a serpentine coil antenna includes a reaction chamber(110), an antenna(120), and an RF power supply(132). The inside of the reaction chamber(110) is in a state of vacuum. The antenna(120) is installed at an upper part of the reaction chamber. The antenna is used for ionizing reaction gases injected into the inside of the reaction chamber and generating plasma. The RF power supply(132) is connected to the antenna in order to supply the RF power to the antenna. The antenna is formed with a plurality of coils having different radiuses. One of the coils is formed with a serpentine coil, which is wound in zigzags along the circumferential direction.
    公开号:KR20040033562A
    申请号:KR1020020062701
    申请日:2002-10-15
    公开日:2004-04-28
    发明作者:이영동；톨마체프유리；김성구；신재광
    申请人:삼성전자주식회사；
    IPC主号:
    专利说明:

    Inductively coupled plasma generating apparatus with serpentine coil antenna
    [29] The present invention relates to an inductively coupled plasma generator, and more particularly, to an inductively coupled plasma generator having an antenna having a structure capable of improving the uniformity of plasma.
    [30] Currently, a technique using low pressure / low temperature plasma is widely used in the microfabrication process of a substrate for manufacturing a semiconductor device or a flat display panel. That is, plasma is widely used to etch a surface of a wafer for manufacturing a semiconductor device or a substrate for manufacturing a liquid crystal display (LCD) or to deposit a predetermined material film on the surface. In particular, in the etching of a substrate or a thin film deposition process for manufacturing a semiconductor device having a high degree of integration, equipment using plasma is gradually increasing. Accordingly, development of a plasma generator suitable for each process has become a key element in semiconductor manufacturing and equipment development. In the recent development of plasma equipment for semiconductor processing, the main focus is the ability to meet the large area of the substrate for improving the yield and the ability to perform the high integration process. That is, maintaining the high plasma density and improving the uniformity of the wafer processing process according to the large area from the existing 200mm wafer to the recent 300mm wafer is the element technology to be solved first. Plasma equipment that has been used in the semiconductor manufacturing process until now is largely classified into capacitive coupled plasma (CCP), electron cyclotron resonance (ECR), helicon, and inductively coupled plasma (ICP). It is currently proposed. Among these, inductively coupled plasma (ICP) equipment has an advantage of easily obtaining a high density / high uniform plasma compared to other equipment, and in particular, its structure is simple and attracts attention as a next-generation equipment for a 300mm large area wafer. However, the implementation of ICP equipment for 300mm wafers by simply expanding the size of the existing ICP equipment for 200mm wafers is limited due to the difficulty of antenna design which is the basis of ICP discharge.
    [31] 1 is a view showing a schematic configuration of a conventional inductively coupled plasma generator.
    [32] As shown in FIG. 1, the inductively coupled plasma generator includes a reaction chamber 10 having a plasma formation space therein. An electrostatic chuck 12 for supporting a substrate, for example, a wafer W, is provided below the reaction chamber 10, and a top of the cover 11 of the reaction chamber 10 includes a dielectric window, 16) is installed. The gas inlet 14 for injecting the reaction gas into the reaction chamber 10 is formed on the side wall of the reaction chamber 10, and a plurality of gases connected to the gas inlet 14 in the reaction chamber 10. A gas distribution port 15 is provided. A vacuum suction port 18 connected to the vacuum pump 19 is formed on the bottom wall of the reaction chamber 10, thereby making the inside of the reaction chamber 10 into a vacuum state. In addition, a coil antenna 20 is installed above the dielectric window 16 to generate plasma in the reaction chamber 10.
    [33] RF power is connected to the coil antenna 20 so that RF current flows. A magnetic field is generated by the RF current flowing through the coil antenna 20, and an electric field is induced inside the reaction chamber 10 by the change of the magnetic field over time. At the same time, the reaction gas is introduced into the reaction chamber 10 through the gas distribution port 15, and the electrons accelerated by the induced electric field ionize the reaction gas through the collision process to generate plasma in the reaction chamber 10. do. The generated plasma is processed, for example, etched, as desired, through the chemical reaction with the surface of the wafer (W). On the other hand, another RF power source is generally connected to the electrostatic chuck 12 to provide a bias voltage for increasing the energy of ions exiting the plasma and impinging on the wafer W.
    [34] Figure 2 shows an example of a conventional spiral coil antenna, Figures 3a and 3b shows the distribution of the induced electric field and the density distribution of the plasma inside the reaction chamber by the spiral coil antenna shown in FIG.
    [35] As shown in FIG. 2, the most commonly used spiral coil antenna 30 now consists of a single conductor coil wound in a spiral. According to such a spiral coil antenna 30, there is a disadvantage that the induced electric field strength is not uniform. That is, as shown in FIG. 3A, the intensity of the induced electric field is relatively weak at the center portion and the edge portion of the antenna, and the intensity of the induction electric field is at the middle portion between them. Will appear strong. Accordingly, as shown in FIG. 3B, the density of plasma generation is highest between the center portion and the edge portion of the reaction chamber, that is, the middle portion. In this way, the plasma generated intensively in the middle of the reaction chamber is diffused to the lower wafer. Therefore, even in the vicinity of the wafer surface where the plasma reacts with the wafer, the plasma density of the middle portion is the highest, and the plasma density is relatively high due to the plasma diffused from the middle portion of the antenna, whereas the edge portion has a plasma density. Will be lowered. If the plasma density distribution is non-uniform, a problem arises in that the etching depth of the substrate or the thickness of the deposited material film varies depending on the position. In particular, as the size of the ICP equipment increases, the diameter of the reaction chamber increases, so that the non-uniformity of the plasma density distribution becomes more severe.
    [36] In addition, in order to maintain a high plasma density in the reaction chamber, the radius of the antenna 30 and the number of turns of the coil should be increased as the size of the ICP equipment increases. Accordingly, the inductance of the antenna 30 may be increased. There is a problem that is increased. When the inductance of the antenna 30 is increased, the voltage applied to the antenna 30 is increased, resulting in capacitive coupling of the RF power. Since the capacitive coupling increases the kinetic energy of the ions excessively, it is difficult to precisely control the process, and ions having high kinetic energy collide strongly with the inner wall of the reaction chamber to generate particles. In addition, there is a problem that the plasma discharge efficiency is lowered by the capacitive coupling.
    [37] 4A and 4B show the distribution of radial components of a magnetic field generated in a conventional circular coil antenna. 4A and 4B, the left side shows the structure of the antenna and the distribution of the radial component B r of the magnetic field generated by the antenna, and the right side shows the radial component of the magnetic field according to the distance from the center of the antenna ( It is a graph showing the intensity of B r ). The graph on the right shows the results of simulation of the distribution of the radial component ( B r ) of the magnetic field formed 5 cm downward from the center of the antenna coil cross section using Vector Fields, an electromagnetic field analysis software. At this time, it is assumed that the current flowing through each coil constituting the antenna flows uniformly throughout the cross section of the coil.
    [38] The antenna shown in FIG. 4A is an antenna composed of three circular coils having a radius of 7 cm, 14 cm and 21 cm, respectively, arranged in concentric circles, each coil having a square cross section having a width and a height of 6 mm, respectively. The directions of the currents are the same.
    [39] In this way, when the current flowing through each coil is the same, the strength of the magnetic field is the highest near the middle of the antenna, and the strength of the magnetic field is still high even near the center of the antenna. Plasma, which is mainly generated at the high magnetic field, spreads to the entire reaction chamber through the diffusion process. In the case of the above magnetic field distribution, the plasma density decreases from the center of the reaction chamber toward the edge. do.
    [40] The antenna shown in FIG. 4B has the same structure as the antenna shown in FIG. 4A, but currents flowing in adjacent coils flow in opposite directions.
    [41] In this case, when the directions of currents flowing in adjacent coils are opposite to each other, as shown in FIG. 13, the inductance of the antenna is reduced by approximately 50% compared to the inductance of the antenna shown in FIG. 4A. It is difficult to expect an improvement in plasma uniformity due to the peak of magnetic field strength near the center.
    [42] 5A to 5D illustrate various types of antennas proposed to solve the problems of the conventional coil antenna described above.
    [43] The antenna 40 shown in FIG. 5A is disclosed in US Pat. No. 5,346,578. The top cover 44 of the reaction chamber 42 is formed in a dome shape, and a conventional spiral coil is formed in a dome shape thereon. It is rolled up. Such a dome-shaped antenna 40 has an advantage of obtaining high plasma uniformity due to its geometric characteristics.
    [44] However, the dome-shaped upper cover 44 is difficult to manufacture and there is a problem of thermal expansion stress due to the antenna 40, and also the length of the coil wound in a circular shape from the upper end to the lower end of the upper cover 44 As it becomes very long, there is a problem that the inductance of the antenna 40 becomes large and a low RF frequency must be used. In particular, as the size of the equipment is enlarged for 300 mm wafers, the number of turns and the radius of the antenna 40 are increased together, thereby making the problem as described above more serious.
    [45] The antenna 50 shown in FIG. 5B is disclosed in US Pat. No. 5,401,350. The helical coil antenna 50a is installed on the upper portion of the reaction chamber 52, and the solenoid shape is formed outside the side wall of the reaction chamber 52. The winding antenna 50b is provided separately to compensate for the low plasma density at the edge of the reaction chamber 52 which is a problem of the conventional spiral coil antenna. However, this antenna 50 has the problem of the conventional spiral antenna as it is, and also has the disadvantage that the process parameters that need to be adjusted from the outside, because it uses two independent RF power supply.
    [46] In fact, the inductively coupled plasma generator using the antenna shown in Figs. 5A and 5B uses a significantly lower RF frequency than the 13.56 MHz standard frequency.
    [47] The antenna 60 shown in FIG. 5C is disclosed in US Pat. No. 6,291,793, which differs from a single spiral antenna connected in series in series, with multiple spiral coils 62 branching in parallel. 64, 66). Such a multi-parallel antenna 60 has an advantage that the inductance of the antenna 60 is lowered as the number of branching coils 62, 64, 66 increases. However, there is no distinct feature that can ensure the uniformity of the plasma, and it has been reported that the uniformity of the plasma is not satisfactory.
    [48] The antenna 70 shown in FIG. 5D is disclosed in US Pat. No. 6,288,493, antenna coils using variable capacitors 76 connected to a plurality of circular coils 71, 72, 73, 74 branched in parallel. LC resonance can be induced between (71, 72, 73, 74). Therefore, the magnitude and phase of the current can be adjusted to ensure high plasma uniformity, and antenna inductance, which is a characteristic of the parallel structure, is low. It may be said to be the antenna of the most advanced concept among the antennas made of circular coils developed to date. However, when LC resonance occurs between the antenna coils 71, 72, 73, and 74 branched in parallel, an excessive current flows in the outermost coil 74, causing an arc ( arc) occurs.
    [49] As described above, the conventional antennas have a disadvantage in that it is difficult to secure uniformity of high plasma by appropriately coping with the change in process conditions due to the above problems. In particular, in recent years, as the size of the wafer is increasing in size, it is increasingly difficult to maintain the uniformity of the plasma density distribution in the vicinity of the wafer edge with a conventional antenna structure, which significantly increases the quality and yield of the semiconductor device. Dropped.
    [50] The present invention has been made to solve the above problems of the prior art, the first object is to improve the plasma uniformity, reduce the antenna inductance, meandering coil antenna having a structure capable of suppressing capacitive coupling The present invention provides an inductively coupled plasma generator.
    [51] Another object of the present invention is to provide an inductively coupled plasma generator having an antenna having a structure that facilitates initial plasma discharge by using LC resonance and secures high plasma uniformity.
    [1] 1 is a view showing a schematic configuration of a conventional inductively coupled plasma generator.
    [2] 2 is a view showing an example of a conventional spiral coil antenna.
    [3] 3a and 3b show the distribution of the induced electric field and the plasma density in the reaction chamber by the spiral coil antenna shown in FIG.
    [4] 4A and 4B show the distribution of radial components of the magnetic field generated in a conventional circular coil antenna.
    [5] 5A to 5D are diagrams illustrating other examples of a conventional coil antenna.
    [6] 6 is a cutaway perspective view illustrating a configuration of an inductively coupled plasma generator having a meandering coil antenna according to a first embodiment of the present invention.
    [7] FIG. 7 is an enlarged perspective view of the meandering coil antenna illustrated in FIG. 6.
    [8] 8 is a graph showing a change in antenna inductance according to the cross-sectional shape of the coil.
    [9] 9 is a graph showing a change in antenna inductance according to the number of coils, their cross-sectional shape, and the direction of current flowing through each coil.
    [10] FIG. 10 is a plan view illustrating a meandering coil antenna provided in an inductively coupled plasma generator according to a second exemplary embodiment of the present invention.
    [11] 11 is a plan view illustrating a meandering coil antenna provided in an inductively coupled plasma generator according to a third exemplary embodiment of the present invention.
    [12] 12A-12G show various examples of meandering coil antennas and the distribution of the radial component of the magnetic field generated at each of them.
    [13] FIG. 13 is a graph showing the results of calculating the inductances of the circular coil antennas shown in FIGS. 4A and 4B and the meandering coil antennas shown in FIGS. 12A to 12G.
    [14] 14 is a plan view illustrating the arrangement of a meandering coil antenna and a permanent magnet provided in the inductively coupled plasma generator according to the fourth embodiment of the present invention.
    [15] FIG. 15 is a plan view illustrating an arrangement of a meandering coil antenna, a matching network, and a capacitor connected in parallel for inducing LC resonance in the inductively coupled plasma generator according to the fifth embodiment of the present invention.
    [16] 16 is a circuit diagram illustrating an L-type matching network connected to an antenna.
    [17] 17A to 17D are graphs for describing LC resonance phenomena according to a change in reactance caused by a capacitor in the fifth embodiment shown in FIG. 15.
    [18] <Explanation of symbols for the main parts of the drawings>
    [19] 110.Reaction chamber 111.Top cover
    [20] 112 ... electrostatic chuck 114 ... gas inlet
    [21] Gas distributor 116 Dielectric window
    [22] 118 vacuum inlet 119 vacuum pump
    [23] 120,220,320,420,520 ... meander coil antenna
    [24] 122,222,226,322,422,522 ... round coil
    [25] 124,224,324,326,424,426,524,526 ... meander coil
    [26] 128,228a, 228b, 328a, 328b ... connection coil
    [27] 132,232,332,532 ... RF Power 530 ... Matching Network
    [28] 534 Capacitors
    [52] The present invention to achieve the above object,
    [53] A reaction chamber inside which is maintained in a vacuum state;
    [54] An antenna installed at an upper portion of the reaction chamber to induce an electric field to generate plasma by ionizing a reaction gas injected into the reaction chamber; And
    [55] An RF power source connected to the antenna for supplying an RF power to the antenna;
    [56] The antenna includes a plurality of coils having different radii, and at least one of the plurality of coils is a meandering coil wound in a zigzag shape along the circumferential direction. .
    [57] According to a first preferred embodiment of the present invention, the antenna comprises a circular coil disposed on the center of the antenna, and a meandering coil disposed outside the circular coil and connected to the circular coil.
    [58] According to a second preferred embodiment of the present invention, the antenna includes a first circular coil disposed on a central portion thereof, a meandering coil disposed outside the first circular coil and connected to the first circular coil, and the meandering coil. It is arranged on the outside of the second coil consisting of a coil connected to the meandering coil.
    [59] According to a third preferred embodiment of the present invention, the antenna includes a circular coil disposed on a central portion thereof, a first meander coil disposed outside the circular coil and connected to the circular coil, and an outer portion of the first meander coil. And a second meander coil disposed on the side and connected to the first meander coil.
    [60] In the above embodiments, it is preferable that the radius of the circular coil is relatively small in order to reduce the area of adjacently opposed portions between the circular coil and the meandering coil.
    [61] In addition, the zigzag shape of the meandering coil is preferably repeated a plurality of times at equal intervals along the circumferential direction.
    [62] The meandering coil also has a plurality of outer portions extending radially and a plurality of inner portions bent over the center portion. The inner portion is preferably disposed near the center of the reaction chamber for a gentle increase in magnetic field components. On the other hand, since the magnetic field component generated in the outer portion is rapidly reduced to the outside, the outer portion is preferably disposed at a position corresponding to the edge portion of the substrate in the reaction chamber.
    [63] In addition, the connection between the plurality of coils is made by a connection coil, the connection coil is preferably disposed in a vertical position higher than the plane in which the plurality of coils are placed in order to minimize the effect.
    [64] In addition, in order to minimize the effect of the capacitive coupling with the plasma, it is preferable that each of the plurality of coils has a rectangular cross section whose width is smaller than the height.
    [65] Meanwhile, each of the plurality of coils may have a circular cross section. This is desirable to prevent an increase in resistance due to a non-uniform distribution of currents flowing along the surface of each of the plurality of coils. In the case where the cooling water passage is formed inside each of the plurality of coils, each of the plurality of coils preferably has a circular cross section in order to smooth the flow of the cooling water through the cooling water passage.
    [66] Meanwhile, according to the fourth preferred embodiment of the present invention, a plurality of permanent magnets may be disposed outside the reaction chamber along the circumferential direction.
    [67] In the above embodiment, it is preferable that the plurality of permanent magnets are disposed in a region where the strength of the magnetic field formed by the antenna is relatively weak.
    [68] In addition, the plurality of permanent magnets may be rotatably installed around the central axis of the reaction chamber in order to optimize the arrangement thereof, and may adjust the position according to the intensity distribution of the magnetic field formed by the antenna.
    [69] According to such a configuration, the inductance of the antenna is lowered, the influence of the capacitive coupling is minimized, and the uniformity of the plasma can be improved.
    [70] And the present invention,
    [71] A reaction chamber whose interior is maintained in a vacuum state;
    [72] An antenna installed at an upper portion of the reaction chamber to induce an electric field to generate plasma by ionizing a reaction gas injected into the reaction chamber;
    [73] An RF power source connected to the antenna for supplying an RF power to the antenna; And
    [74] And a capacitor disposed in parallel with the antenna between the RF power supply and the matching network of the antenna and the antenna.
    [75] According to a fifth preferred embodiment of the present invention, the plurality of coils constituting the antenna may be connected in series to the RF power source.
    [76] On the other hand, at least some of the coils constituting the antenna may be connected in parallel to the RF power source.
    [77] According to such a configuration, it is possible to discharge and maintain the plasma efficiently by using the LC resonance phenomenon by the capacitor.
    [78] Hereinafter, with reference to the accompanying drawings will be described in detail preferred embodiments of the inductively coupled plasma generating apparatus according to the present invention.
    [79] 6 is a cutaway perspective view illustrating a configuration of an inductively coupled plasma generator having a meandering coil antenna according to a first embodiment of the present invention, and FIG. 7 is an enlarged perspective view of the meandering coil antenna illustrated in FIG. 6. .
    [80] 6 and 7 together, the inductively coupled plasma generator according to the present invention uses a plasma generated by the antenna 120 to etch or onto a surface of a substrate for manufacturing a semiconductor device, for example, a wafer (W). A semiconductor manufacturing apparatus for microfabrication such as depositing a predetermined material film on a substrate.
    [81] The inductively coupled plasma generator includes a reaction chamber 110 having a plasma formation space therein. The inside of the reaction chamber 110 is maintained in a vacuum state, and for this purpose, a vacuum suction port 118 connected to the vacuum pump 119 is formed on the bottom wall of the reaction chamber 110. An electrostatic chuck 112 for supporting a substrate, for example, a wafer W, is provided below the inside of the reaction chamber 110, and an RF power source 134 is connected to the electrostatic chuck 112 to generate in the reaction chamber 110. A bias voltage is provided so that the ions escaped from the plasma can collide with the surface of the wafer W with a sufficiently high energy. The dielectric window 116 is installed in the upper cover 111 of the reaction chamber 110 to allow the RF power to pass therethrough. The gas inlet 114 for injecting the reaction gas into the reaction chamber 110 is formed on the side wall of the reaction chamber 110, and a plurality of gas distribution ports 115 connected to the gas inlet 114 are formed in the reaction chamber. It may be provided inside the 110.
    [82] In addition, an antenna 120 is installed above the reaction chamber 110, that is, above the dielectric window 116 to induce an electric field for generating plasma by ionizing the reaction gas injected into the reaction chamber 110. An RF power source 132 for supplying an RF power is connected to the antenna 120. Therefore, RF current flows through each coil constituting the antenna 120. Accordingly, a magnetic field is generated by the right-screw law of ampere, and Faraday electromagnetic induction is generated inside the reaction chamber 110 by the change of the magnetic field over time. The electric field in the circumferential direction is induced according to the law. The induced electric field accelerates electrons, and the electrons ionize the reaction gas introduced into the reaction chamber 110 through the gas distribution port 115 to generate plasma.
    [83] As shown in FIG. 7, the antenna 120 includes a circular coil 122 disposed on a central portion thereof and a serpentinecoil 124 disposed outside the circular coil 122. The meandering coil 124 is wound windingly in a zigzag form along the circumferential direction, and the zigzag form is repeated a plurality of times at equal intervals along the circumferential direction. The number of repetitions in a zigzag form depends on the radius of the antenna 120. Although it may be six times as shown, when the radius of the antenna 120 is large, it may be eight or more times, and the radius of the antenna 120 may be increased. This small case may be less than six times. The meandering coil 124 has a plurality of radially extending outer portions 124a and a plurality of inner portions 124b that are bent toward the circular coil 122 above the center. The inner portion 124b of the meander coil 124 is disposed adjacent to the circular coil 122 for a gentle increase of the magnetic field component. In addition, since the magnetic field component generated in the outer portion 124a of the meandering coil 124 is rapidly reduced to the outside, the outer portion 124a is disposed at a position corresponding to the edge of the wafer in the reaction chamber 110. do. This meandering coil 124 has an advantage that the inductance of the antenna 120 is lowered since the surrounding area is reduced compared to the conventional circular coil that can be made with the same length.
    [84] Meanwhile, although the bent edge portion of the meandering coil 124 is angularly formed in FIGS. 6 and 7, the bent edge portion may be rounded for ease of fabrication. This is the same for all of the antennas shown in the figures below.
    [85] The radius of the circular coil 122 and the inner radius and the outer radius of the meandering coil 124 may be appropriately adjusted according to the size of the reaction chamber 110. In particular, in order to reduce the effect of capacitive coupling, the radius of the circular coil 122 and the inner radius of the meandering coil 124 are preferably as small as possible. This is because the area of the inner portion 124b of the meandering coil 124 facing adjacent to the circular coil 122 becomes small, so that the capacitance of the antenna 120 is reduced. However, if the radius of the circular coil 122 and the inner radius of the meandering coil 124 is too small, the manufacturing becomes difficult when the cooling water passage is formed inside the coils 122 and 124 as described below. Since the resistance becomes large, the radius of the circular coil 122 and the inner radius of the meandering coil 124 should be determined in consideration of this point.
    [86] On the other hand, in the case where a coolant passage (not shown) is formed inside the coils 122 and 124, the cross section of each of the coils 122 and 124 may be circular in order to smooth the flow of the coolant through the coolant passage. In addition, when the cross sections of the coils 122 and 124 are circular, an increase in resistance due to an uneven distribution of currents flowing along the surfaces of the coils 122 and 124 may be prevented.
    [87] In the meandering antenna 120 having the above-described structure, the reaction chamber is performed through an optimization process such as a radius of the circular coil 122, a difference between an outer radius and an inner radius of the meandering coil 124, and a zigzag-shaped repetition cycle. The distribution of the magnetic field formed in 110 may be adjusted. Since the distribution of the magnetic field directly affects the uniformity of the generated plasma, the uniformity of the plasma can be improved by controlling the distribution of the magnetic field. This will be described later.
    [88] Meanwhile, one end of the circular coil 122 is grounded, and one end of the meandering coil 124 is connected to the RF power source 132. Meanwhile, an RF power source 132 may be connected to one end of the circular coil 122, and one end of the meander coil 124 may be grounded. The other end of the circular coil 122 and the other end of the meandering coil 124 are connected by the connection coil 128. The connection coil 128 may be disposed at a position sufficiently higher in the vertical direction than the plane in which the circular coil 122 and the meandering coil 124 are placed. In this case, the influence of the connection coil 128 on the plasma generation can be ignored.
    [89] In addition, each of the circular coil 122 and the meandering coil 124 preferably has a rectangular cross-sectional shape whose width is smaller than the height when the cross-sectional area is fixed. As described above, according to the coils 122 and 124 having a narrow cross section, the inductance of the antenna 120 is reduced. This will be described in detail with reference to FIG. 8.
    [90] 8 is a graph showing a change in the antenna inductance (L) according to the cross-sectional shape of the coil. The graph shown in FIG. 8 shows the results of calculating the inductance of the antenna by varying the width and height of the cross section of each coil in the antenna consisting of three circular coils having a radius of 7 cm, 14 cm and 21 cm, respectively. At this time, it is assumed that the current flows uniformly along the surface of each coil.
    [91] Referring to the graph of FIG. 8, it can be seen that the inductance of the antenna decreases as the width of the coil cross section increases or the height of the coil cross section increases. On the other hand, when the cross-sectional area of the coil is fixed constantly, it can be seen that the antenna inductance when the cross-sectional width of the coil is narrow and the height is higher than the antenna inductance when the cross-sectional width of the coil is high and the height is low. For example, the cross-sectional area of the coil is the same as 36㎟ However, a width of 1mm and a height of 36mm, compared to the cross section of the inductance coil with (L 1) is the inductance of the coils with the cross section the width and height of 6mm, respectively (L 2) Appears low.
    [92] Referring to FIG. 7 again, the circular coil 122 and the meandering coil 124 are wound in opposite directions. Therefore, the direction of the current flowing in the circular coil 122 and the meandering coil 124 is reversed, there is an advantage that the inductance of the antenna 120 is lowered. This will be described in detail with reference to FIG. 9. However, if necessary, the circular coil 122 and the meandering coil 124 may be wound in the same direction.
    [93] 9 is a graph showing a change in antenna inductance L according to the number of coils, their cross-sectional shape, and the direction of current flowing through each coil. In Fig. 9, the graph of ① shows the result of calculating the inductance when the directions of the currents flowing through the coils are the same in the antenna consisting of four circular coils having a radius of 5.25 cm, 10.5 cm, 15.75 cm, and 21 cm, respectively. The graph of ② shows the result of calculating the inductance when the direction of current flowing through each coil is the same in the antenna consisting of three circular coils with radius of 7 cm, 14 cm and 21 cm, respectively. And, the graph of ③ shows the result of calculating the inductance when the directions of the currents flowing in neighboring coils in the antenna of the four circular coils are opposite, and the graph of ④ is the three circular coils described above. The result of calculating the inductance when the directions of the currents flowing in the coils adjacent to each other in the antenna are opposite are shown.
    [94] 9, it can be seen that the antenna inductance is low when the number of coils constituting the antenna is small and when the direction of the current flowing in the neighboring coil is reversed. In particular, it can be seen that the increase and decrease of the antenna inductance according to the direction of the current is much larger than that of the antenna inductance according to the number of coils. Therefore, even if the number of coils increases, reversing the direction of the current flowing in the neighboring coils can significantly reduce the antenna inductance.
    [95] As described above, according to the first embodiment of the present invention, the antenna inductance can be efficiently reduced by adjusting the cross-sectional shape of the coil and the direction of the current flowing through the coil, thereby applying a high frequency RF power to the antenna. can do.
    [96] FIG. 10 is a plan view illustrating a meandering coil antenna provided in an inductively coupled plasma generator according to a second exemplary embodiment of the present invention.
    [97] The antenna 220 illustrated in FIG. 10 includes a first circular coil 222 disposed on a central portion thereof, a meandering coil 224 disposed outside the first circular coil 222, and the meandering coil 224. It consists of a second circular coil 226 disposed outside of. That is, the antenna 220 has a structure in which another circular coil 226 is disposed at the outermost side in addition to the coil arrangement of the antenna 120 illustrated in FIG. 7. Therefore, since the shape, action and effects of the meandering coil 224 are the same as in the above-described first embodiment, redundant descriptions thereof will be omitted. The second circular coil 226 is disposed to be adjacent to the outer portion of the meander coil 224. For example, the distance between the second circular coil 226 and the outer portion of the meandering coil 224 may be approximately 1 cm. In such an antenna 220, the density of the plasma generated at the edge portion of the antenna 220 due to the outermost second circular coil 226 has the advantage that it is higher than in the first embodiment described above, Peaks can be spread radially and circumferentially. This will also be described later.
    [98] Meanwhile, one end of the first circular coil 222 is grounded, and one end of the second circular coil 226 is connected to the RF power source 232. The other end of the first circular coil 222, one end of the meandering coil 224, the other end of the meandering coil 224, and the other end of the second circular coil 226 are connected by connecting coils 228a and 228b, respectively. . The connecting coils 228a and 228b are also disposed at a sufficiently high position from the plane in which the first and second circular coils 222 and 226 and the meandering coil 224 are placed in order to minimize the influence on the plasma generation.
    [99] Each of the coils 222, 224, and 226 may have a rectangular cross-sectional shape having a smaller width than the height as in the first embodiment, and may have a circular cross-sectional shape as necessary. In addition, the coils adjacent to each other are wound in opposite directions to the opposite direction of the current flowing through them. As described above, the antenna 220 having such a structure has an advantage of reducing inductance.
    [100] 11 is a plan view illustrating a meandering coil antenna provided in an inductively coupled plasma generator according to a third exemplary embodiment of the present invention.
    [101] The antenna 320 illustrated in FIG. 11 includes a circular coil 322 disposed on a central portion thereof, a first meandering coil 324 disposed outside the circular coil 322, and the first meandering coil 324. It consists of a second meandering coil 326 disposed outside of. That is, the antenna 320 has a structure in which another meandering coil 326 is disposed at the outermost side in addition to the coil arrangement of the antenna 120 illustrated in FIG. 7. In other words, the antenna 320 has a structure in which the outermost second circular coil 226 of the antenna 220 illustrated in FIG. 10 is replaced with the second meandering coil 326. The first meandering coil 324 is the same as the meandering coil 124 of the antenna 120 illustrated in FIG. 7. The second meandering coil 326 is also wound zigzag in a circumferential direction, and the zigzag form is repeated a plurality of times at equal intervals along the circumferential direction. The number of times in which the second meander coil 326 has a zigzag repetition may be the same as that of the first meander coil 324. In addition, an inner radius of the second meander coil 326 may be smaller than an outer radius of the first meander coil 324. That is, the inner portion of the second meander coil 326 may be arranged to enter between the outer portions of the first meander coil 324.
    [102] In the antenna 320 having such a structure, it is possible to easily adjust the distribution of the magnetic field strength formed at the edge of the reaction chamber by using the outermost meandering coil 326. That is, the optimum plasma uniformity can be adjusted through the proper arrangement of the outermost meandering coil 326 in a zigzag form.
    [103] As shown in FIG. 13, when the outermost meandering coil is properly disposed, despite the increase in the number of coil turns due to the addition of the outermost meandering coil as in the three-turn coil antenna of FIG. 12G, the two-turn coil of FIG. 12E. The inductance of the antenna is further reduced than without the outermost meandering coil, such as an antenna.
    [104] Referring back to FIG. 11, one end of the circular coil 322 is grounded, and one end of the second meander coil 326 is connected to the RF power source 332. In addition, the connection between the circular coil 322 and the first and second meandering coils 324 and 326 and the arrangement of the connection coils 328a and 328b are also the same as in the above-described embodiment. In addition, the cross-sectional shape of each of the coils 322, 324, and 326, the winding direction, and the direction of the current are also the same as in the above-described embodiment, and the effects thereof are also the same as in the above-described embodiment.
    [105] Hereinafter, various examples of the meandering coil antenna, the distribution of the radial component of the magnetic field generated in each of the antennas, and the inductance of each antenna will be described with reference to FIGS. 12A to 12G and 13.
    [106] 12A to 12G, the left side shows the structure of the meandering coil antenna and the distribution of the radial component B r of the magnetic field generated by the antenna, and the right side shows the radial direction of the magnetic field according to the distance from the center of the antenna. It is a graph which shows the intensity of component ( B r ). The graph on the right shows the distribution of the radial component ( B r ) of the magnetic field formed 5 cm downward from the antenna along any three radial lines through the center of the antenna. The simulation results are shown. At this time, it is assumed that the current flowing through each coil constituting the antenna flows uniformly throughout the cross section of the coil.
    [107] 13 is a graph showing the results of calculating the inductance L of the circular coil antenna shown in FIGS. 4A and 4B and the meandering coil antenna shown in FIGS. 12A to 12G.
    [108] The antenna shown in FIG. 12A consists of a circular coil having a radius of 7 cm and positioned on its center, and two meandering coils arranged outside of the circular coil and having an average radius of 14 cm and 21 cm, respectively. The meandering coil having an average radius of 14 cm is repeatedly wound four times at regular intervals along the circumferential direction in a zigzag form, so that the difference between the outer radius and the inner radius is 2 cm. The meandering coil having an average radius of 21 cm is repeatedly wound 12 times at equal intervals along the circumferential direction in a zigzag shape so that the difference between the outer radius and the inner radius is 6 cm. In addition, each coil has a square cross section having a width and a height of 6 mm, respectively, and the directions of currents flowing in neighboring coils are opposite.
    [109] In the antenna shown in FIG. 12A, the coil on the center of the coil is a circular coil, and there is no difference between the outer radius and the inner radius. It has a structure. The inductance of such an antenna has a relatively low value as shown in the graph of FIG. 13. In addition, in the graph showing the distribution of the magnetic field strength on the right side of FIG. 12A, the outermost peak has an advantage that the width of the outermost peak is wider and moves to the outer side more than the antenna shown in FIG. 4B. However, the height of the peak is lowered, and furthermore, there is no change in the height of the peak generated near the center, so it is difficult to expect the improvement of the plasma uniformity.
    [110] The antenna shown in Fig. 12b is two circular coils arranged first and third from the center and having a radius of 7 cm and 16.1 cm, respectively, and two meandering coils of a second and fourth placed with an average radius of 10.3 cm and 21 cm, respectively. Is made of. The meandering coil having an average radius of 10.3 cm is wound 8 times at regular intervals along the circumferential direction in an zigzag form, so that the difference between the outer radius and the inner radius is 5.4 cm. The meandering coil having an average radius of 21 cm is wound 8 times at regular intervals along the circumferential direction and zigzag-shaped so that the difference between the outer radius and the inner radius is 8 cm. In addition, each coil has a square cross section having a width and a height of 6 mm, respectively, and the directions of currents flowing in neighboring coils are opposite.
    [111] In the antenna shown in FIG. 12B, despite the increase in the number of coils, the inductance of the antenna remains low as shown in the graph of FIG. In addition, there is an advantage that the width of the outermost magnetic field peak becomes wider, and the height of the peak generated near the center is considerably lowered. Therefore, the antenna of such a structure can predict the improvement of the uniformity of plasma.
    [112] The antenna shown in FIG. 12C comprises a circular coil having a radius of 16.1 cm and a meandering coil disposed outside of the circular coil and having an average radius of 21 cm. The meandering coil is repeatedly wound 8 times at equal intervals along the circumferential direction in a zigzag form so that the difference between the outer radius and the inner radius is 8 cm. Each coil has a square cross section with a width and height of 6 mm, respectively, and the direction of the current flowing through the two coils is reversed.
    [113] The antenna shown in FIG. 12C is an antenna that simplifies the structure while adopting the advantages of the antenna structure shown in FIG. 12B. The inductance of this antenna has a significantly low value as shown in the graph of FIG. In addition, two magnetic field strength peaks are formed far from the center of the antenna. Therefore, the antenna of such a structure can anticipate the significant improvement of plasma uniformity.
    [114] The antenna shown in Fig. 12d is composed of a circular coil having a radius of 3 cm and a meandering coil having an average radius of 14.3 cm and disposed outside the circular coil. The meandering coil is repeatedly wound 8 times at equal intervals along the circumferential direction in a zigzag form so that the difference between the outer radius and the inner radius is 22 cm. Each coil has a square cross section with a width and height of 6 mm, respectively, and the direction of the current flowing through the two coils is reversed.
    [115] The antenna shown in FIG. 12D has the same structure as the antenna shown in FIG. 12C, but the circular coil disposed on the center portion has a smaller radius. In the antenna having such a structure, as shown in the graph of FIG. 13, the antenna inductance is slightly increased compared to the antenna illustrated in FIG. 12C, but is still lower than that of the conventional simple circular coil antenna illustrated in FIG. 4A. . In addition, since the area of the antenna shown in FIG. 12d adjacent to each other between the circular coil and the meandering coil becomes smaller, the capacitance of the antenna is reduced, thereby reducing the influence of capacitive coupling. It is predicted. And, as the distribution of magnetic field strength shows, the difference between the radius of the circular coil on the center and the outer and inner radius of the meandering coil and the optimization of the zigzag repetition period are compared with those of the simple circular coil antenna and the spiral coil antenna. It can be seen that the uniformity can be improved a lot.
    [116] The antenna shown in FIG. 12E is a meandering antenna having a basic structure adopted in the first preferred embodiment of the present invention shown in FIGS. 6 and 7 described above. This antenna has the same coil arrangement as the antenna of FIG. 12d, and the opposite direction of the current flowing through the two coils is also the same as that of FIG. 12d. However, in order to observe the effect of the coil having a rectangular cross section, the antenna of FIG. 12E differs from the antenna of FIG. 12D in that each coil has a rectangular cross section having a width of 1 mm and a height of 36 mm.
    [117] In the antenna of such a structure, as shown in the graph of FIG. 13, the antenna inductance is considerably lower than that of the antenna shown in FIG. 12d, and is similar to that of the antenna shown in FIG. 12d, but more gentle toward the edges. It shows the distribution of increasing magnetic field strength. Accordingly, the antenna shown in FIG. 12E has the advantage of the antenna of FIG. 12D described above, and also has the advantage of reducing the antenna inductance, thereby enabling inductively coupled discharge using a high frequency.
    [118] The antenna shown in Fig. 12F is an antenna adopted in the second preferred embodiment of the present invention shown in Fig. 10 described above. This antenna has a form in which a circular coil is further disposed on the outermost side in addition to the basic coil arrangement of the antenna shown in FIG. 12E. The distance between the outermost circular coil and the meandering coil inside thereof is 1 cm, and each coil has a rectangular cross section as described above, and the directions of currents flowing in neighboring coils are opposite.
    [119] In the antenna having such a structure, as shown in FIG. 13, a low antenna inductance can be maintained, and the peak of the magnetic field strength generated by the circular coil and the meandering coil on the center due to the outermost circular coil is shown in FIG. 12E. It is slightly further outward compared to the peak of the magnetic field strength shown in FIG. Therefore, the density of the plasma generated at the edge portion of the antenna can be higher.
    [120] The antenna shown in Fig. 12G is an antenna adopted in the third preferred embodiment of the present invention shown in Fig. 11 described above. This antenna has a form in which a meandering coil is further disposed at the outermost side in addition to the coil arrangement of the antenna shown in FIG. 12E. That is, the antenna has a form in which the outermost circular coil of the antenna shown in FIG. 12F is replaced with a meandering coil. Each coil of this antenna also has a rectangular cross section as described above, and the directions of currents flowing in adjacent coils are opposite.
    [121] In the antenna of such a structure, as shown in FIG. 13, low antenna inductance can be maintained, and the distribution of the outermost magnetic field strength can be adjusted in the radial direction and the circumferential direction by using the outermost meandering coil. Therefore, it can be predicted that the optimum plasma uniformity can be adjusted through the proper arrangement of the zigzag shape of the outermost meandering coil.
    [122] On the other hand, in the case of inductively coupled plasma discharge, capacitive coupling generated by applying a high voltage to the antenna causes high plasma potential and reduces the generation efficiency and uniformity of the plasma. Therefore, the antenna design must be considered to minimize the effects of capacitive coupling. In addition, it is possible to discharge at low pressure by improving the inductive coupling ability with the plasma, and low inductance for efficient impedance matching when increasing the frequency to obtain a plasma having high density and low electron temperature. You will need an antenna with. As described above, the antenna according to the present invention has a meandering coil having a smaller area compared to the total length of the coil, and also has a reversed direction of current flowing in adjacent coils, and each coil has a high cross section. This results in a significantly lower inductance. As described above, in the case of an antenna having a low inductance, even when a high RF frequency is used, the impedance can be kept sufficiently low, so that the potential difference across the antenna is lowered, thereby reducing the effect of capacitive coupling. Contamination by particles generated by collision with the dielectric window can be prevented. Furthermore, if the radius of the circular coil disposed above the center is reduced, the area of the adjacent parts facing each other between the coils becomes smaller, so that the capacitance of the antenna is reduced, and if the width of the coil is reduced, the area facing the dielectric window is reduced. This reduces the capacitive coupling between the antenna and the plasma.
    [123] 14 is a plan view illustrating the arrangement of a meandering coil antenna and a permanent magnet provided in the inductively coupled plasma generator according to the fourth embodiment of the present invention.
    [124] Referring to FIG. 14, a meandering coil antenna 420 is installed at an upper portion of the reaction chamber 410, and a plurality of permanent magnets 440 are disposed outside the reaction chamber 410 along the circumferential direction. The plurality of permanent magnets 440 are arranged to cross the N pole and the S pole along the circumferential direction.
    [125] The meandering coil antenna 420 includes a circular coil 422 disposed on the center portion, a first meandering coil 424 and a second meandering coil 426 disposed outside the circular coil 422. Since the meandering coil antenna 420 illustrated has the same structure as the meandering coil antenna in the above-described third embodiment, further description thereof will be omitted. The meandering coil antenna 420 may be replaced with the meandering coil antenna of the first or second embodiment described above.
    [126] The plurality of permanent magnets 440 is preferably disposed at a region where the strength of the magnetic field formed by the antenna 420 is relatively weak. In the case of the illustrated antenna 420, as shown in FIG. 12G, since the outer portions of the two meandering coils 424 and 426 are relatively weak in the strength of the magnetic field in the adjacent portion, the permanent magnet 440 Are disposed at positions facing the outer portions of the four meandering coils 424, 426.
    [127] On the other hand, when the structure of the antenna 420 is changed, since the intensity distribution of the magnetic field is also changed, it is preferable that the position of the permanent magnet 440 is also changed. To this end, the permanent magnet 440 is preferably rotatably installed to adjust its position.
    [128] As described above, in the fourth embodiment of the present invention, the reaction chamber 410 includes a plurality of permanent magnets 440 so as to complement the local magnetic poles generated by the meandering coil antenna 420. ) To be placed outside. The permanent magnet 440 disposed as described above has an effect of confining the plasma by the magnetic field, which is called a multi-pole confinement effect. That is, when the N pole and the S pole of the permanent magnet 440 are disposed to cross along the circumference of the reaction chamber 410, a magnetic mirror effect is induced at the edge of the reaction chamber 410, thereby charging particles. As a result, wall loss is reduced and the plasma density at the edge of the reaction chamber 410 is increased, and the uniformity of the plasma may be improved. On the other hand, the magnetic field by the permanent magnet 440 is concentrated only on the edge portion of the reaction chamber 410 so that most of the plasma inside the reaction chamber 410 is not affected by the magnetic field by the permanent magnet 440. In the meandering coil antenna 420, a portion having a relatively weak magnetic field along the circumferential direction may be formed, and the permanent magnet 440 may be disposed in the portion to more effectively use the multi-pole confinement effect.
    [129] As described above, according to the fourth embodiment of the present invention, the plasma density can be improved by reducing the wall loss of the electrons using the multi-pole confinement effect, and the electron density is increased at the edge of the reaction chamber to increase the plasma uniformity. Can be secured. In addition, by manufacturing so as to adjust the position of the permanent magnet according to the structure of the meandering coil antenna, it is possible to optimize the plasma characteristics according to the change of the process conditions.
    [130] FIG. 15 is a plan view illustrating arrangement of a meandering coil antenna, a matching network, and a capacitor included in the inductively coupled plasma generator according to the fifth embodiment of the present invention.
    [131] Referring to FIG. 15, a capacitor 534 in parallel with a meander coil antenna 520 is provided between a matching network 530 connecting the RF power source 532 and the meander coil antenna 520 and the meander coil antenna 520. ) Is installed.
    [132] The meandering coil antenna 520 includes a circular coil 522 disposed on the center portion, a first meandering coil 524 and a second meandering coil 526 disposed outside the circular coil 522. Since the meandering coil antenna 520 illustrated has the same structure as the meandering coil antenna in the above-described third embodiment, description thereof will be omitted. The meandering coil antenna 520 may be replaced with the meandering coil antenna of the first or second embodiment described above. In addition, the meandering coil antenna 520 may be replaced by a conventional circular coil antenna or a spiral coil antenna. That is, the fifth embodiment of the present invention can be applied to an antenna having any structure.
    [133] The coils 522, 524, and 526 constituting the meandering coil antenna 520 may be connected in series to the RF power source 532 as shown. Although not shown, some or all of the coils 522, 524, and 526 may be connected in parallel to the RF power source 532. That is, the capacitor 534 is disposed in parallel with the antenna 520, but the coils 522, 524, and 526 themselves constituting the antenna 520 are connected in parallel or in series. As such, the antenna inductance may be appropriately adjusted by connecting the coils 522, 524, and 526 in parallel or in series as necessary.
    [134] As described above, in the fifth embodiment of the present invention, the capacitor 534 is connected in parallel between the meandering coil antenna 520 and the matching network 530, thereby easily discharging the initial plasma using LC resonance. And it is possible to ensure the stability of the process using an inductively coupled plasma.
    [135] As described above, in the case of the ICP discharge, after the initial discharge process through the capacitive coupling by the initial high antenna voltage, the inductive coupling discharge process is led by the induction electric field induced from the alternating current flowing through the antenna coil. The threshold breakdown voltage required for such capacitive coupling is affected by the process pressure or the gas used. However, when the inductance of the antenna is low, such as an antenna in which neighboring coils are squeezed in opposite directions, the initial plasma through capacitive coupling requires a large potential difference because the potential difference of the antenna is not large enough unless a very high RF power is used. It becomes difficult to discharge. However, when the LC resonance phenomenon through proper pre-setting of the matching network is used, a large potential difference can be induced even in the case of an antenna having a low inductance, thereby enabling initial discharge through capacitive coupling.
    [136] Hereinafter, the method will be described with reference to FIGS. 16 and 17A to 17D. FIG. 16 illustrates an L-type matching network, which is a representative buck connected to an ICP antenna, and FIGS. 17A to 17D illustrate LC resonance phenomena according to a change in reactance caused by a capacitor in the fifth embodiment of FIG. 15. Graphs are shown.
    [137] Referring to FIG. 16, the matching network 530 connecting the RF power source 532 and the antenna 520 includes two variable capacitors C 1 and C 2 . As described above, the capacitors 534 and C 3 are connected in parallel between the matching network 530 and the antenna 520. Resistor R 1 , represented in this equivalent circuit, takes into account ohmic loss in matching network 530.
    [138] FIG. 17A is a graph showing resonance phenomena of the antenna impedance Z, and FIG. 17B is a graph showing an enlarged initial set point of FIG. 17A. 17A and 17B, ReZ represents a real part of the antenna impedance Z.
    [139] As shown in FIGS. 17A and 17B, the capacitor C 3 connected in parallel with the antenna changes the input impedance Z of the antenna. For example, when an RF frequency of 13.56 MHz is used, and the inductance La of the antenna 520 is 300 nH and the resistance R 0 of the antenna 520 is 0.1 ohm, the reactance of the capacitor C 3 is set. (Xc) shows LC resonance at 25.65 ohms (C = 458 Hz). Before the plasma is generated, the Q-factor of the ICP antenna is higher than after the plasma is generated, so that the width of the resonance peak is very narrow. At such a resonance point, the impedance Z of the antenna increases for a given RF power, so that the voltage difference of the antenna becomes very large, and it becomes very difficult to match the antenna to the RF power supply. If the matching condition is not met, a significant reflection of the RF power from the antenna will result and the plasma discharge cannot be made efficiently.
    [140] To solve this problem, the preset point of the matching network is chosen as a point slightly off the exact resonance point. That is, as shown in FIGS. 17A and 17B, the point where the capacitance of the capacitor C 3 is 355 ㎊ and the reactance Xc is 33 ohm is selected. Under these conditions, the reactance Xc is large enough to match, and furthermore, the electrical characteristics of the antenna connected to the matching network have the characteristics of an inductor, so that only two variable capacitors C 1 and C 2 are used. The matching condition can be satisfied by using a simple L-type matching network. Assuming that R 1 and R 2 shown in FIG. 16 are 0.05 ohms, respectively, the capacitance of each of the two capacitors C 1 and C 2 required for matching is 1,000 ㎊ and 115 경우 when using a 50 ohm cable having a length of 3 m. Can be obtained by calculation These capacitances are in the range that can be easily obtained in most matching networks.
    [141] If the initial set point of the matching network is selected with the conditions obtained from the above calculation before plasma discharge occurs, and the input RF power is 500Watt, the current and voltage flowing through the ICP antenna are reacted by the capacitor (C 3 ). According to the change of (Xc), the resonance characteristics as shown in FIGS. 17C and 17D are shown. That is, when the capacitance of the capacitor C 3 , which is a resonance condition, is 355 ㎊, the antenna voltage is increased to about 1,600 Volt to be sufficient to cause plasma initial discharge. When the plasma is generated, the antenna resistance is increased to decrease the voltage and current of the antenna. For example, when the antenna resistance R 0 , which is 0.1 ohm before the plasma generation, increases to 1.0 ohm after the plasma generation, the electrical characteristics of the antenna, which exhibited resonance phenomena such as curve 1 shown in FIGS. 17C and 17D before the plasma discharge, may be reduced. After the plasma generation, the characteristics as shown in the curve 2 are shown. After the plasma generation, the matching network automatically finds a matching condition. In the process of switching from curve 1 to curve 2, a lot of current flowing to the antenna facilitates the transition from the capacitively coupled discharge characteristic to the inductively coupled discharge characteristic to maintain the plasma characteristics stably.
    [142] The capacitance of each of the two capacitors (C 1 , C 2 ) satisfying the resonance conditions obtained above may be different from the resonance conditions obtained through experiments. However, it is not necessary to correctly select the initial setpoint of the matching network from the beginning to find the resonance condition. After reducing the pressure sufficiently to mTorr to prevent plasma discharge in the chamber, select the initial set point and apply RF power with the matching network set to automatic mode to find the exact resonance condition before the plasma discharge occurs. I can make it.
    [143] As described above, when the LC resonance between the antenna and the capacitor is used, the initial plasma is easily generated, and the plasma of the high density can be stably maintained. In particular, such a structure can be usefully applied even when a Faraday shield is installed between the antenna and the dielectric window. In addition, as described above, by connecting each coil constituting the meandering coil antenna in parallel or in series, it is possible to adjust the antenna inductance for optimal plasma discharge as needed.
    [144] Although the present invention has been described with reference to the disclosed embodiments, these are merely exemplary, and it will be understood by those skilled in the art that various modifications and equivalent other embodiments are possible. Therefore, the true technical protection scope of the present invention will be defined by the appended claims.
    [145] As described above, the inductively coupled plasma generating apparatus according to the present invention has the following effects.
    [146] First, the uniformity of the plasma may be improved by controlling the distribution of the magnetic field formed in the reaction chamber through an optimization process such as a difference between the outer and inner radii of the meandering coil and a zigzag repetition period. And, by adjusting the cross-sectional shape of the coil and the direction of the current flowing through the coil as necessary, it is possible to efficiently reduce the antenna inductance, thereby enabling efficient plasma discharge using a high frequency. In addition, it is possible to minimize the effect of the capacitive coupling.
    [147] Second, by arranging a plurality of permanent magnets outside the reaction chamber, it is possible to improve plasma uniformity and to secure high plasma density at the edge of the reaction chamber by using the multi-pole confinement effect. In addition, the plasma characteristics may be optimized by adjusting the position of the permanent magnet according to the structure of the meandering coil antenna.
    [148] Third, by inducing LC resonance by connecting a capacitor in parallel between the antenna and the L-type matching network, it is easy to discharge the initial plasma, thereby securing the stability of the process using the inductively coupled plasma.
    权利要求:
    Claims (24)
    [1" claim-type="Currently amended] A reaction chamber inside which is maintained in a vacuum state;
    An antenna installed at an upper portion of the reaction chamber to induce an electric field to generate plasma by ionizing a reaction gas injected into the reaction chamber; And
    An RF power source connected to the antenna for supplying an RF power to the antenna;
    The antenna comprises a plurality of coils having different radii, wherein at least one of the plurality of coils is a meander coil coiled in a zigzag shape along the circumferential direction.
    [2" claim-type="Currently amended] The method of claim 1,
    The antenna is inductively coupled plasma generator characterized in that the circular coil is disposed on the center and the meandering coil is disposed outside the circular coil and connected to the circular coil.
    [3" claim-type="Currently amended] The method of claim 2,
    Inductively coupled plasma generator, characterized in that the radius of the circular coil is formed to be relatively small in order to reduce the area of the adjacently facing portion between the circular coil and the meandering coil.
    [4" claim-type="Currently amended] The method of claim 1,
    The antenna may include a first circular coil disposed on a central portion thereof, a meandering coil disposed outside the first circular coil and connected to the first circular coil, and disposed outside the meandering coil and connected to the meandering coil. Inductively coupled plasma generator, characterized in that consisting of a second circular coil.
    [5" claim-type="Currently amended] The method of claim 4, wherein
    And said second circular coil is disposed adjacent to an outer portion of said meandering coil.
    [6" claim-type="Currently amended] The method of claim 1,
    The antenna may include a circular coil disposed on a central portion thereof, a first meander coil disposed outside the circular coil and connected to the circular coil, and disposed outside the first meander coil and connected to the first meander coil. Inductively coupled plasma generator, characterized in that consisting of a second meander coil.
    [7" claim-type="Currently amended] The method of claim 6,
    Inductively coupled plasma generator, characterized in that the number of times of repeating the zigzag form of the first and second meander coil.
    [8" claim-type="Currently amended] The method of claim 6,
    And an inner radius of the second meandering coil is smaller than an outer radius of the first meandering coil.
    [9" claim-type="Currently amended] The method of claim 1,
    The zigzag shape of the meandering coil is repeated in multiple times at equal intervals along the circumferential direction.
    [10" claim-type="Currently amended] The method of claim 9,
    The meandering coil has a plurality of outer portions extending radially and a plurality of inner portions bent over the center portion.
    [11" claim-type="Currently amended] The method of claim 10,
    And an inner portion of the meandering coil is disposed near a central portion of the reaction chamber, and the outer portion is disposed at a position corresponding to an edge portion of the substrate in the reaction chamber.
    [12" claim-type="Currently amended] The method of claim 1,
    The coupling between the plurality of coils is made by a connection coil, the connection coil is inductively coupled plasma generating device, characterized in that arranged in a vertical position higher than the plane in which the plurality of coils are placed.
    [13" claim-type="Currently amended] The method of claim 1,
    Inductively coupled plasma generator, characterized in that each of the plurality of coils has a rectangular cross-section less than the height.
    [14" claim-type="Currently amended] The method of claim 1,
    Inductively coupled plasma generator, characterized in that each of the plurality of coils has a circular cross section.
    [15" claim-type="Currently amended] The method of claim 1,
    Inductively coupled plasma generating device, characterized in that a plurality of permanent magnets are disposed in the circumferential direction outside the reaction chamber.
    [16" claim-type="Currently amended] The method of claim 15,
    The plurality of permanent magnets are inductively coupled plasma generator, characterized in that arranged in the circumferential direction so that the north pole and the south pole.
    [17" claim-type="Currently amended] The method of claim 15,
    The plurality of permanent magnets are inductively coupled plasma generating device, characterized in that arranged in a region where the strength of the magnetic field formed by the antenna is relatively weak.
    [18" claim-type="Currently amended] The method of claim 15,
    The plurality of permanent magnets are rotatable about a central axis of the reaction chamber is inductively coupled plasma generating device, characterized in that to adjust the position according to the intensity distribution of the magnetic field formed by the antenna.
    [19" claim-type="Currently amended] The method of claim 1,
    And a capacitor is installed between the RF power supply and the matching network of the antenna and the antenna in parallel with the antenna.
    [20" claim-type="Currently amended] The method of claim 19,
    The plurality of coils constituting the antenna is inductively coupled plasma generator, characterized in that connected to the RF power in series.
    [21" claim-type="Currently amended] The method of claim 19,
    At least some of the plurality of coils constituting the antenna are connected to the RF power source in parallel.
    [22" claim-type="Currently amended] A reaction chamber whose interior is maintained in a vacuum state;
    An antenna installed at an upper portion of the reaction chamber to induce an electric field to generate plasma by ionizing a reaction gas injected into the reaction chamber;
    An RF power source connected to the antenna for supplying an RF power to the antenna; And
    And a capacitor installed in parallel with the antenna between the RF power supply and the matching network of the antenna and the antenna.
    [23" claim-type="Currently amended] The method of claim 22,
    And a plurality of coils forming the antenna are connected in series to the RF power supply.
    [24" claim-type="Currently amended] The method of claim 22,
    At least some of the plurality of coils constituting the antenna are connected to the RF power supply in parallel.
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    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    法律状态:
    2002-10-15|Application filed by 삼성전자주식회사
    2002-10-15|Priority to KR20020062701A
    2004-04-28|Publication of KR20040033562A
    2005-05-03|Application granted
    2005-05-03|Publication of KR100486724B1
    优先权:
    申请号 | 申请日 | 专利标题
    KR20020062701A|KR100486724B1|2002-10-15|2002-10-15|Inductively coupled plasma generating apparatus with serpentine coil antenna|
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